/*
  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
  Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)

  Stockfish is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdint.h>
#include <algorithm>
#include <cassert>
#include <cctype>
#include <cstddef>
#include <iosfwd>
#include <istream>
#include <map>
#include <ostream>
#include <sstream>
#include <string>

#include "evaluate.h"
#include "misc.h"
#include "search.h"
#include "thread.h"
#include "tt.h"
#include "types.h"
#include "uci.h"

using std::string;

namespace Stockfish {

UCI::OptionsMap Options;  // Global object
uint8_t         MateThreatDepth = 1;
bool            ChineseRule     = false;

namespace UCI {

// 'On change' actions, triggered by an option's value change
static void on_clear_hash(const Option&) { Search::clear(); }
static void on_hash_size(const Option& o) { TT.resize(size_t(o)); }
static void on_logger(const Option& o) { start_logger(o); }
static void on_threads(const Option& o) { Threads.set(size_t(o)); }
static void on_mate_threat_depth(const Option& o) { MateThreatDepth = size_t(o); }
static void on_repetition_rule(const Option& o) { ChineseRule = o == "ChineseRule"; }
static void on_eval_file(const Option&) { Eval::NNUE::init(); }

// Our case insensitive less() function as required by UCI protocol
bool CaseInsensitiveLess::operator()(const string& s1, const string& s2) const {

    return std::lexicographical_compare(s1.begin(), s1.end(), s2.begin(), s2.end(),
                                        [](char c1, char c2) { return tolower(c1) < tolower(c2); });
}


// Initializes the UCI options to their hard-coded default values
void init(OptionsMap& o) {

    constexpr int MaxHashMB = Is64Bit ? 33554432 : 2048;

    o["Debug Log File"] << Option("", on_logger);
    o["Threads"] << Option(1, 1, 1024, on_threads);
    o["Hash"] << Option(16, 1, MaxHashMB, on_hash_size);
    o["Clear Hash"] << Option(on_clear_hash);
    o["Ponder"] << Option(false);
    o["MultiPV"] << Option(1, 1, 500);
    o["Move Overhead"] << Option(10, 0, 5000);
    o["Slow Mover"] << Option(100, 10, 1000);
    o["nodestime"] << Option(0, 0, 10000);
    o["Mate Threat Depth"] << Option(1, 0, 10, on_mate_threat_depth);
    o["Repetition Rule"] << Option("AsianRule var AsianRule var ChineseRule", "AsianRule",
                                   on_repetition_rule);
    o["UCI_ShowWDL"] << Option(false);
    o["EvalFile"] << Option(EvalFileDefaultName, on_eval_file);
}


// Used to print all the options default values in chronological
// insertion order (the idx field) and in the format defined by the UCI protocol.
std::ostream& operator<<(std::ostream& os, const OptionsMap& om) {

    for (size_t idx = 0; idx < om.size(); ++idx)
        for (const auto& it : om)
            if (it.second.idx == idx)
            {
                const Option& o = it.second;
                os << "\noption name " << it.first << " type " << o.type;

                if (o.type == "string" || o.type == "check" || o.type == "combo")
                    os << " default " << o.defaultValue;

                if (o.type == "spin")
                    os << " default " << int(stof(o.defaultValue)) << " min " << o.min << " max "
                       << o.max;

                break;
            }

    return os;
}


// Option class constructors and conversion operators

Option::Option(const char* v, OnChange f) :
    type("string"),
    min(0),
    max(0),
    on_change(f) {
    defaultValue = currentValue = v;
}

Option::Option(bool v, OnChange f) :
    type("check"),
    min(0),
    max(0),
    on_change(f) {
    defaultValue = currentValue = (v ? "true" : "false");
}

Option::Option(OnChange f) :
    type("button"),
    min(0),
    max(0),
    on_change(f) {}

Option::Option(double v, int minv, int maxv, OnChange f) :
    type("spin"),
    min(minv),
    max(maxv),
    on_change(f) {
    defaultValue = currentValue = std::to_string(v);
}

Option::Option(const char* v, const char* cur, OnChange f) :
    type("combo"),
    min(0),
    max(0),
    on_change(f) {
    defaultValue = v;
    currentValue = cur;
}

Option::operator int() const {
    assert(type == "check" || type == "spin");
    return (type == "spin" ? std::stoi(currentValue) : currentValue == "true");
}

Option::operator std::string() const {
    assert(type == "string");
    return currentValue;
}

bool Option::operator==(const char* s) const {
    assert(type == "combo");
    return !CaseInsensitiveLess()(currentValue, s) && !CaseInsensitiveLess()(s, currentValue);
}


// Inits options and assigns idx in the correct printing order
void Option::operator<<(const Option& o) {

    static size_t insert_order = 0;

    *this = o;
    idx   = insert_order++;
}


// Updates currentValue and triggers on_change() action. It's up to
// the GUI to check for option's limits, but we could receive the new value
// from the user by console window, so let's check the bounds anyway.
Option& Option::operator=(const string& v) {

    assert(!type.empty());

    if ((type != "button" && type != "string" && v.empty())
        || (type == "check" && v != "true" && v != "false")
        || (type == "spin" && (stof(v) < min || stof(v) > max)))
        return *this;

    if (type == "combo")
    {
        OptionsMap         comboMap;  // To have case insensitive compare
        string             token;
        std::istringstream ss(defaultValue);
        while (ss >> token)
            comboMap[token] << Option();
        if (!comboMap.count(v) || v == "var")
            return *this;
    }

    if (type != "button")
        currentValue = v;

    if (on_change)
        on_change(*this);

    return *this;
}

}  // namespace UCI

}  // namespace Stockfish
